#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9) + 7;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }



signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	freopen("A-small-attempt0.in", "r", stdin);
	freopen("A-small-attempt0.txt", "w", stdout);
	//freopen("in.txt", "r", stdin);
	//freopen("out.txt", "w", stdout);
	int T; cin >> T;
	for (int t = 0; t < T; t++) {
		int R, C; cin >> R >> C;
		vector<vector<char>> v(R, vector<char>(C));
		rep(i, 0, R) rep(j, 0, C) { cin >> v[i][j]; }
		rep(i, 0, R)rep(j, 1, C) {
			if (v[i][j] == '?') {
				v[i][j] = v[i][j - 1];
			}
		}
		rep(i, 0, R)rrep(j, 0, C - 1) {
			if (v[i][j] == '?') {
				v[i][j] = v[i][j + 1];
			}
		}
		rep(i, 1, R) {
			if (v[i][0] == '?') {
				rep(j, 0, C) {
					v[i][j] = v[i - 1][j];
				}
			}
		}
		rrep(i, 0, R - 1) {
			if (v[i][0] == '?') {
				rep(j, 0, C) {
					v[i][j] = v[i + 1][j];
				}
			}
		}
		cout << "Case #" << t + 1 << ":" << endl;
		rep(i, 0, v.size()) {
			cout << v[i][0];
			rep(j, 1, v[i].size()) { cout << v[i][j]; }
			cout << endl;
		}
	}
	return 0;
}